The present invention relates to the purification of drinking water, and more particularly, to replaceable filter cartridges used in household water filtration systems.
Many appliances and refrigerators are equipped with door-mounted drinking water and ice dispensers. Some appliances and refrigerators incorporate their own dedicated water filtration system, such as those disclosed in U.S. Pat. No. 7,000,894 to Olson, et. al. Those dedicated filtration systems employ a removable filter cartridge which is typically replaced every several months. Those filters use a projection that extends from the nozzle-end of the filter cartridge to actuate a bypass valve in a head assembly or manifold mounted in the appliance. The manifold is configured to receive the nozzles and projection described in that patent. The replacement cost of these filters from the manufacturer of the appliance is high as the appliance manufacturer attempts to configure the filter cartridges in ways that enable the manufacturer to make it difficult for others to make the cartridge, thus creating a captive market for which the original manufacturer is the sole supplier and for which the manufacturer can charge a premium price. There is thus a need for a filter cartridge that can replace such filter cartridges as they wear out, but that is available at a lower cost.
Projections extending from the ends of filter cartridges are used for numerous purposes. These purposes include aligning the filter cartridge in the manifold, stabilizing the cartridge in the manifold, or actuating shut-off-valves that allow water to flow only when the filter cartridge is present and shut off flow when the cartridge is removed. The location and shape of such projections may vary. But if the projections must extend any large distance into the manifold then the long projections are subject to damage during shipping, handling, installation and removal of the filter cartridge. Moreover, the longer the projection the more prone it is to being displaced so it may not readily mate with the corresponding recess in the manifold. There is thus a need for a filter cartridge with a shorter projection that may nonetheless reach locations within the manifold.
The inlet and outlet nozzles must extend into the manifold to mate with corresponding fittings in the manifold and the nozzle length can become long enough to subject the nozzles to potential damage or deflection during shipping, handling or installation of the filter cartridge. When the inlet and outlet nozzles are separated as in U.S. Pat. No. 7,000,894 to Olson, the nozzles must have thick walls to provide the needed strength and stability. There is a need for a way to strengthen and stabilize the nozzles.
For some applications, like those in U.S. Pat. Nos. 7,610,932 and 7,000,894 to Olson, the relative location of the nozzles and a projection are important. When the nozzles or projection become long, the relative position of the ends of the nozzles and the projection are more subject to variation and those ends must mate readily with the corresponding recesses in the manifold. There is thus a need for a filter cartridge that stabilizes the relative positions of the nozzles and any actuating projection.
These water filters are held in the manifold by bayonet lugs on the cartridge neck, or by cams or mounting assemblies on the elongated body of the filter cartridge. Examples of such mounting assemblies on the filter cartridge are found in U.S. Pat. Nos. 7,147,773 and 8,627,675.
One difficulty with the above filter cartridges is that occasionally the water in the manifold becomes cold enough to freeze and then the filter cartridge is difficult to extract from the manifold and from the retaining mechanism. U.S. Pat. No. 8,627,675 uses a lever insertion and removal mechanism and the mechanical advantage offered by the lever helps remove filter cartridges where the inlet or outlet has frozen. But even with the removal achieved users typically want to quickly clear the ice from the inlet or outlet and immediately reinsert the filter cartridge for use and the current nozzle and manifold designs make that difficult. There is thus a need for an improved filter cartridge that makes it easier to clear ice from frozen inlet or outlet nozzles in the cartridge, and that facilitates clearing ice from the manifold inlet and outlet receptacles.